Process for separating and concentrating minerals



April 9, 1940. M CONSTANT 2,196,457

PROCESS FOR SEPARATING AND CONCENTRATING MINERALS l Filed March 10, 1937 2 Sheets-Sheet 1 ZZ IIVVVEHEOR. z

ATTORNEYS.

April 9, 1940. M, CQNSTANT 2,196,457

PROCESS FOR SEPARATING AND CONCENTRATING MINERALS I Filed March 1o, 1957 2 sheets-sheet 2 BY/gww. M.

ATTORNEYS Patented pr. 49, 1940 N UNI-TED STATES PROCESS .Fon SEARATING AND I i.

ooNoENTRATINdMINERALs v 'Maurice Constant, Scobey`,'l',vont. l Application March V1o, 193s, serial -Naisvmzio 1o claims.l (o1. 209-423) My invention relates to processes for separating and concentrating minerals.

.The objects of my invention are to afford a process by which very Vune gold, silver or other mineral particlesrnay be. separated from pulp,`

slime, placermaterial or other liquid mechanical mixtures thereof, byconcurrent .precipitation and notation, or byv precipitation alone. My process isparticularly applicable to recoveryof so-called Various forms of apparatus may be util-izedfor carrying out. my process. .One form of apparatus suitable for that .purpose is illustrated in' vthe drawings yaccornpanyingy this amendment, inr lwhich-4 'a tank. This tank is preferably made with va height and length of approximately twelve feet and its width is preferablyffrom one-sixth to onequarter of its length, although` thedimensions may be varied to suit the requirementsl of the particular placer ground to .be worked.

At the front orvr left end of the tank -is a feed. hopper, 6, into which the mixture oi placer ground and water is fedfan'dfrom which it flows'downwardly into.- the upper end of a riille box, `v5t,- which is preferably providedV with a screen, 3l', to carry off the coarsermaterialand .through which the finer material may pass and by gravitational action the' particles of metal, being heavierthan the waste, will be deposited upon the bottomof the sluice which may be `provided with grooves, riilles, or anyvoth'ery suitable device for catching and advancing the particles of metal to the outlet, 4|.

kThe riilie box ismounte'd upon hangers, t2, which are pivoted in the tank and vmay be driven by a motor connected to the riiiie box by a connecting rod, 68, or other 'suitable meansi y'I'he riie box is preferably sloped with' the,

rear end extending downwardly at an angle `pro'- portidnateto the speed of the current and the time requisite to permit gravitational subsidence and deposition of the metal particles. The larger andheavier the particles of metal, and the cleaner and clearer the mixture, the more rapid will` be the subsidence Sand deposition, but the;` iiner the' particles and the more clay'for other colloidal matter vcarrierinthe mixture, the slower will be the subsidence and deposition. Infgeneral, a slope of .fromone to six inches vper foot Awill be found )practical for .thecommoner forms' of vplacer material. AThe iiow of current along the riilie box will also be rvgovf-irnedto some'exten't by the rate at which ther'nixture is fed intoy the hopper or apron, 6, andthe size ofthe openingprovided by the door-drgate, 84, .which'is slidingly moimt-r ed uponv the' front vend of the tank in position to regulate the Iopening through 'which the feed must pass. .i f i Baiiie plates, y29, are provided :which 4extend clear across the tankabove `the riiiie box and have downward extensions which/extend down` wardly on both sides ofthe riiilebox.

The' purpose ofthese .battles is to'preventforward 'movement of the :general body of water in lthe tank and to connethe current rof placerA material as closely las possible to the rifil'e box. Atk the Sametime', the position ofthese bai-lies permits free upward' movement" of Athev water which 'may be fed to the tank through the .supply pipe, .16, with openings into' thejbottorn of the tank "at 1.1., f'IVand 11", through which water may befed into the tank and `cause an upwardly moving current at the sides vci and above the rif fle box.v At the'fsametime a horizontal screen', 28, is mounted` in the upper part ofA the tank through which the water maypassv yand carry any of the .ne particles of metal having Isuf'c'rent buoyancy 'to be Ifloated, and vsuch particles of metal may be raked from the 'screen by traveling rakes, 21, carried by the belt,y 2li, passing over suitable pulleys',`l8 and 212. These rakes lcarry' Lthe metalf-and the water floating i-t, to a dis-- charge pipe, 90, from which it is discharged through thel outlet, 86, into a strainer yor dewaterer, 8 1.

A eisehargefopening, nms'providoin the tot! tom of the riillebox throughv whichl precipitates may be discharged through the fpipe, 38, and below the opening, 4|, va une screen, 32, may be mounted in thev oor Iof the kriiile box having a .small compartment, 34, underv the screen liilled with buckshot, 33, between which 'fine particles of metal may-also lodge 'and from which they may be carried 'off 'and discharged through the outlet, 31, after passing through a funnel, 35', through the pipe, 3B.

The lower end of they rime boxpreferably ex-.

tends outwardly through therear wall, I, of the tank and into a tailings chamber from' which it maybe carriedL by an elevator, 1, provided with' s 'k buckets, '8; An overflow outlet, li'ib, maybe 'proa vidednear the top of the tailings chamber and an additional outlet, ma, may be formed in the bottom of the tailings chamber for cleanout purposes.`

It will be understood that the apparatus shown, which is substantially that covered `by my copending application for apparatus patent, is merely illustrative of one form of apparatus by which my process can be carried out. rVarious other meansv may be devised by which a current of placer material may be subjected to pressure corresponding to the pressure existing at a substantial depth in a body of water. Forinstance, the mixture can be fed into a closed tank wherein it may be subjected to air pressure. of the riille box or sluice may have wide variations. Likewise, the vibratory movement of the rile box may be varied or' even` entirely omitted.

It is well known to those skilled in the art that in certain kinds of placer material some of the finegold appears to be` greasy, and either because of being mixed or coated with some greasy or oily substance, or because of certain chemical combinations, it will float or travel at or near the top of a stream of fluid. z

Itis also well known that in some placer material, as well as in certain pulps, slimes jand pulverized ores, there will exist a percentage of metal l particles too'ne to readily precipitate. I have found that panning or manipulating such mixtures at a depth of several feet below the surface of a body of liquid will cause precipitation of such particles. l

My process `not only permits recovery of metal particles too fine to be precipitated by ordinary means, butalso facilitates and speeds up the subsidence and deposition of fine particles which may be recovered, although at a much slower rate byprocesses heretofore in use.

In order to carry out my process, I provide means by `whichthe slime, pulp or other mechanical mixture of pulverized ore and water, is fed into a large, deep, tank at a considerable depth below the surface of the water or other fluid therein, and is then conducted slowly over and along a rilebox at a substantial depth below the surface. .Meanwhile the rillleV box is vibratedl with a rapid, reciprocatory, longitudinal movement.`

I also mount in the tank, partitions or other means extending downwardly from the surface to a short distanceabove the vibratory rile box at comparatively short intervals and these partitions have the effect of preventing rapid longitudinal movement and longitudinal wave movement of the fluid in the tank. The sluice `or rile box is inclined downwardly from the feed end at a substantial angle, preferably of from one to six inches per foot. But the pitch may be varied to suit different types or classes of material to be separated. l

Extending longitudinally of the `tank approximately `at the surface level of the fluid therein contained, I mount a screen preferably of about fifteenA or sixteen meshes to the inch, and extending'lengthwise of the tank at about the middle thereof. I prefer to form this screeny with a width approximating one-third the width ofthe tank and I provide doors or cover `plates hinged to the upper edges of the sides of' the tank and adapted to` extendfrom the sides of 'the `tank to the edges of the screen.. f

A traveling rake is provided, the bars of which extend transversely of the screen'v vand travel; lengthwise ofthe screen from the lfeed toward The form` the discharge end of the tank where an outlet is provided to carry off the scrapings moved by the rake. I

At the bottom of the tank and below the sluice, I provide a plurality of inlets by which fresh water may be constantly brought into the tank to create an upward current at the sides of the riflie box. The lower end of the rifile box extends outwardly through` the foot-wall of the tankvand into an elevator chamber from which the accumulating tailings may be carried `by a suitable elevator. l The riflle box is preferably suspended upon swinging arms which may be suitably connected by a longitudinal rod extending through a pack- .ingin the head of the tank, to be driven by a cam, crank, or other suitable means for the purpose -of vibrating the rile box. I prefer to operate, or at least to assist in operating, the riille box in one direction by a spring which may be either a tension or compression spring as circumstances make most desirable.

The riilies in the riffle box are preferably formed in the form of rectangular grooves one of which extends lengthwise along the middle of the bottom board, with diagonal grooves extending outwardly therefrom and connecting with the central groove. l

The slime'or mixture being led into the tank under a substantial depth of water, any metal particles therein will naturally be pretty thoroughly wetted and as the current moves lengthwiseof the sluice from the feed to the discharge end thereof, the gold. or other mineral which is wet, being heavier than the fluid, will settle toward the sluice board and be precipitated in the rifiles or grooves above described, where the vibratory movement and the slope of the rile box combined, `will cause it to travel to the lower end of the central groove where a discharge pipe is connected to the lower end of the groove, which will carry off the precipitates.

In case any of the precipitates pass the discharge opening in the sluice, they may be caused to pass through a fine screen which is mounted at the lower end of the rilebox on a level with the bottomboard.

Under this screen and spaced therefrom,` I mount another screen and. between `the two screens, I place a charge of buckshot or other suitableqmaterial, adapted to permit downward passage ofthe flnesv through it, and the lower screen discharges intoa sloping chamber that will conduct the material from the lower screen to an outlet pipe fromfwhich it may be drawn off. as desired. l

While the depth of the riflle box and the water level in the tank may be varied as. circumstances require, I prefer to utilize a depth of from four feetto ten.feet,depending somewhat uponthe fineness` of the gold. The ner the gold is, the greater the depth should be. j

Any desired form of riflle box may be used, but I prefer to use'a box comprising a grooved bottom board with side boardsattached thereto.

It will be noted that While my process employs the action of gravity to permit or cause'fthe subsidence and rdeposition of part vof the gold or other metal and the corresponding action of buoyancy or .differential gravitational'action to separatethe iine particlesvr which are floatable, it increases the differential action or the s'eparative action of gravity byucausing such-action to be initiated and to take place at a substantial depth belowthe surface ofthe water.

c l $5,196,218? v Itis dicult 'to explain why the differential vaction of gravity-is thus increased, lbut the fact remains that I havediscovered that such action maybe thus increased 'and my process is applicapleto any means which utilizes this increased differential action by applying substantial pressure to the mixture while iiowing over and along a sluice upon 'which deposition of the metal by gravity is tak-ing .place or by which the lighter The bottom board is preferably provided 'with' a longitudinal rectangular groove extending down therniddle thereof, with oblique rectangular grooves branching -out to each side therefrom and sloping downwardly toward the middlel In the claimslfuse" the term fine goldv vto apply to the'fine particles of gold found in certain types 'of placerl ground, and the terni "flour gold to apply to the superne particles of gold some of which will settle or subsideand some of which have a tendency to float or at least remain in v suspension, and which will not readily subside but which will be readily carried upward in an ascending current of water; and Iuse the term buoyant particles to indicate the aforesaid particles of 'flour gold which will float -or remain in suspension by reason of their fineness, as well as by reason ofvbeing coated or combined with any substance lighter than water,jw'hich will tend to prevent settling or subsidence.

rvThe term substantial pressure is used in the claims to indicate such a pressure as would be produced bya head of water approximately four4 `feet or more, it being well known that the weight of a body of Water is equivalentv to approximately half a pound per square inch for each foot of depth. Wherefore, a head of four feet would produce a pressure of approximately two pounds' per square inch and a head of ten feet would produce a pressure of approximately nve pounds per y square inch.

It is also well known that such pressures are exerted by Ysuch a body of water in all 'directions. Therefore,.when' a current comprising a mixture of placer ground and water is caused to now along'or'through ra `larger body of water at a substantial depth below the surface, it is subjected to a compressive action equivalent to the vpressure per square inch developed at such a n wise. l

It is this increased tendency -of the non-buoyant particles to subside or settle and this increased tendency of the buoyant particles to rise, that my process isdesigned to produce and effectuate, but my process is not intended to be limited to Aauriferous ground, gravel or pulp, but is intended to apply to all other minerals which may be found to be aected in like manner.

Iam aware' that riiile boxes or similar devices have been used which, in operation, were covered with water, and I amaware that means vhave been 'used such as baflles and a gradual increase 'in the cross sectional area of a tank or trough for the purposev of "progressively retardin'g the flow of current therein so as to provide for a diiferential depositior'iof mineral particles.. I am also aware that flotation has been usedto some extent for separating buoyantparticles of mineral, but so far as I am aware, no one prior 'Ito myf-use thereof, hasy rmade'use of the process described by me of increasing the rate and quantity of gravimetric separation of both subsidable and floatable particles of mineral by subjecting a' bodyy or ycurrent fof pulp or a mixture of placer ground and water to the pressure of a substantial head of waterY superimposed thereon varying` "in height in proportion to the requirements of each particular oaseyor of increasing the rate and quantity of flotation byutilizing a slowly movingv upward current of waterv at both sides of and above a stream or body of pulp or an aqueous mixture efplacer ground, in the presence of a superimposed body of water of considerable depth, the depth being varied proportionately to the kind, quality and condi-tion of the mineral particles. In such cases, the best depth must necessarily be -fdetermined by tests made upon'the particular material undergoing treatment, butin most cases, a depth of from four to tenfeet-of superimposed water will be found effective vand enicient.

1. 'I'he method rof increasing the rate of subsidence and deposition of flour gold from a mixture of placer ground-and water, which consists in flowing said mixturein a current conned at 'the' sides and bottom through a relatively much larger body 'of confined water-at a substantial depth, subjecting such current to longitudinal vi-A bratory action beneath such current whereby the gold may be ydeposited by gravitational action, .drawing oiv the precipitates and wastes by separate outlets, providing `an upward `flow of water at the sides of and above the current adapted to carry'upward'therefrom buoyant particles vof gold and raking and discharging said particles.

2; The methodv of accelerating thegravimetric separation of fine gold and 'flour gold in a pulp consisting v'of water and auriferous ground, s and or gravel, which consists in subjecting 'astream of such pulp-to the continuous pressure of a c body of water superimposed thereon, to a height of four feet or more, and simultaneously subjecting the buoyant our gold'to the lifting action of an upwardly moving current of water on both sides` of and above such stream, withdrawing the deposits from the'bed of the stream of pulp, and discharging the flour gold from the surface.

3. The process of simultaneously separating subsidable particles of gold and oatable iiour gold from anaqueous pulp containing both, which consists in causing a current of such mixture to v flow along a downwardly sloping trough under a superimposed bodyof liquid having va head of four feet or more to increase the rate of deposition of the 'heavier particles of gold in the trough, and simultaneously providing an upwardly moving current of water at each side of and above the trough'to carry upwardly the lighterflour gold, then drawing oif the deposit from the trough and raking ofi` the fiour gold from the surface.

4. The method of` accelerating the gravimetric separation of fine particles of metal in a lpulp 75 cnA ' raking ofi the buoyant particles from the surface.

5. The process of separating iiour gold and other ne gold from an aqueous mixture of au-V riferous earth, which consistsin flowing a current of such mixture along a trough inthe lowery part of a larger body of such aqueous mixture at a depth in excess of four feet below the sur face, retaining the larger body of the liquid against forward movement to allow subsidence and deposition of gold particles by gravitational action along the bottomI of such trough, withdrawing such deposit from the trough, providing an upward flow of water at the sides of and above the trough to carry upward buoyant particles of l goldtherein, and raking off and discharging such buoyant particles and then de-watering them through a suitable lter. n A

6.` The process of separating fine particles of metal from a metal-bearing pulp which consists in iiowing a current of-such pulp mixed with water along a trough in the lower part of a larger body of water at a depth in excess of four feet belowl the surface, retaining the largeribody of the liquid against forward movement to allow subsidence and .deposition of such particles by gravitational action along the bottom of such trough, withdrawing 4such deposit from the trough, providing an upward iiow of water at the sides of and above the trough to carry upward buoyant particles of metal therein, and raking oi and discharging such buoyant particles and then de-watering them through aV suitable iilter.l

7. The process of separating flour gold and r other fine gold from an aqueous mixture of auriferous earth, which consists in subjecting a current of such mixture iiowing along a trough to the continuous pressure `of a superimposed` body of such mixtureY `in excess of two pounds per ,square inch, retaining the superimposed liquid against forward movement to allow deposition of subsidable gold particles by gravitational action along the bottom of such trough, withdrawing such deposit from the trough, providing an upward flow of water at both sides of the trough to carry upwardly to the surface buoyant particles of gold, and raking olf and discharging such buoyant particles and then de-waterng them through a suitable lter. Y y

8. The process of separating fine particles of metal from a metal-bearing pulp which consists in subjecting a current of suchrv mixture flowing along a trough tothe continuous pressure of a superimposed body of such mixture in excess of two pounds per square inch, retaining the superimposed liquid against forward movement to allow deposition of subsidable metal particles by gravitational action along the bottom of such trough, withdrawing vsuch deposit from the trouglnproviding an upward flow ofl water at both sides of the trough to carry upwardly to thesurface buoyant particles of metal, and raking off and discharging such buoyant particles and then de-watering them through a suitable filter.

9. The process of separating flour gold and other fine gold from an aqueous mixture of auriferous earth, which consists in flowing a current of such mixture along and through a larger body of such aqueous mixture, at a depthin excess of four feet below the surface, retaining the larger body of the' liquid against forward movement to allow subsidence and depositionof gold particles by gravitational action, withdrawing such deposit and the tailings, providing an upward flow of water at the sides of and above the current to carry upward buoyant particles of gold therein, and raking oi and discharging such buoyant particles and then de-watering them through a Suitable lter.

10. The process ofseparating ne particles of metal from a metal-bearing pulp which consists in flowing a current of such mixture along and through a larger body of such aqueous mixture,

at a depth in excess of four feet below the surface, separating the tailings fromthe metal, retaining the larger body of the liquid against forward movement to allow subsidence and deposition of such particles by gravitational action, withdrawing. such deposit and the tailings, pro

' viding an upward flow of water at the sides of and above the aforesaid current to carry upward buoyant particles of metal therein, and raking oif and y discharging such buoyant particles and then dewatering them through a suitable filter.

MAURICE CONSTANT. 

